Commit 45239ba3 authored by Pawan Gupta's avatar Pawan Gupta Committed by Borislav Petkov (AMD)
Browse files

x86/cpu: Add CPU type to struct cpuinfo_topology 



Sometimes it is required to take actions based on if a CPU is a performance or
efficiency core. As an example, intel_pstate driver uses the Intel core-type
to determine CPU scaling. Also, some CPU vulnerabilities only affect
a specific CPU type, like RFDS only affects Intel Atom. Hybrid systems that
have variants P+E, P-only(Core) and E-only(Atom), it is not straightforward to
identify which variant is affected by a type specific vulnerability.

Such processors do have CPUID field that can uniquely identify them. Like,
P+E, P-only and E-only enumerates CPUID.1A.CORE_TYPE identification, while P+E
additionally enumerates CPUID.7.HYBRID. Based on this information, it is
possible for boot CPU to identify if a system has mixed CPU types.

Add a new field hw_cpu_type to struct cpuinfo_topology that stores the
hardware specific CPU type. This saves the overhead of IPIs to get the CPU
type of a different CPU. CPU type is populated early in the boot process,
before vulnerabilities are enumerated.

Signed-off-by: default avatarPawan Gupta <pawan.kumar.gupta@linux.intel.com>
Co-developed-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Acked-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20241025171459.1093-5-mario.limonciello@amd.com
parent b0979e53

arch/x86/include/asm/intel-family.h

+6 −0
Original line number Diff line number Diff line
@@ -183,4 +183,10 @@ 
/* Family 19 */

#define INTEL_PANTHERCOVE_X		IFM(19, 0x01) /* Diamond Rapids */



/* CPU core types */

enum intel_cpu_type {

	INTEL_CPU_TYPE_ATOM = 0x20,

	INTEL_CPU_TYPE_CORE = 0x40,

};



#endif /* _ASM_X86_INTEL_FAMILY_H */

arch/x86/include/asm/processor.h

+18 −0
Original line number Diff line number Diff line
@@ -105,6 +105,24 @@ struct cpuinfo_topology { 
	// Cache level topology IDs

	u32			llc_id;

	u32			l2c_id;



	// Hardware defined CPU-type

	union {

		u32		cpu_type;

		struct {

			// CPUID.1A.EAX[23-0]

			u32	intel_native_model_id	:24;

			// CPUID.1A.EAX[31-24]

			u32	intel_type		:8;

		};

		struct {

			// CPUID 0x80000026.EBX

			u32	amd_num_processors	:16,

				amd_power_eff_ranking	:8,

				amd_native_model_id	:4,

				amd_type		:4;

		};

	};

};



struct cpuinfo_x86 {

arch/x86/include/asm/topology.h

+9 −0
Original line number Diff line number Diff line
@@ -114,6 +114,12 @@ enum x86_topology_domains { 
	TOPO_MAX_DOMAIN,

};



enum x86_topology_cpu_type {

	TOPO_CPU_TYPE_PERFORMANCE,

	TOPO_CPU_TYPE_EFFICIENCY,

	TOPO_CPU_TYPE_UNKNOWN,

};



struct x86_topology_system {

	unsigned int	dom_shifts[TOPO_MAX_DOMAIN];

	unsigned int	dom_size[TOPO_MAX_DOMAIN];
@@ -149,6 +155,9 @@ extern unsigned int __max_threads_per_core; 
extern unsigned int __num_threads_per_package;

extern unsigned int __num_cores_per_package;



const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c);

enum x86_topology_cpu_type get_topology_cpu_type(struct cpuinfo_x86 *c);



static inline unsigned int topology_max_packages(void)

{

	return __max_logical_packages;

arch/x86/kernel/cpu/debugfs.c

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ static int cpu_debug_show(struct seq_file *m, void *p) 
	seq_printf(m, "die_id:              %u\n", c->topo.die_id);

	seq_printf(m, "cu_id:               %u\n", c->topo.cu_id);

	seq_printf(m, "core_id:             %u\n", c->topo.core_id);

	seq_printf(m, "cpu_type:            %s\n", get_topology_cpu_type_name(c));

	seq_printf(m, "logical_pkg_id:      %u\n", c->topo.logical_pkg_id);

	seq_printf(m, "logical_die_id:      %u\n", c->topo.logical_die_id);

	seq_printf(m, "llc_id:              %u\n", c->topo.llc_id);

arch/x86/kernel/cpu/topology_amd.c

+3 −0
Original line number Diff line number Diff line
@@ -182,6 +182,9 @@ static void parse_topology_amd(struct topo_scan *tscan) 
	if (cpu_feature_enabled(X86_FEATURE_TOPOEXT))

		has_topoext = cpu_parse_topology_ext(tscan);



	if (cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES))

		tscan->c->topo.cpu_type = cpuid_ebx(0x80000026);



	if (!has_topoext && !parse_8000_0008(tscan))

		return;